Abstract:

A walk behind lawn mower has an exit tunnel that is opened and closed by a
pivotal mulch door to convert the mower between collecting and mulching
modes of operation. An operating handle fixed to the mulch door includes
a vertically reciprocal push button for releasing locking tabs that
engage detents for holding the mulch door in the open and closed
positions thereof. The bottom wall of the exit tunnel has a steeply
inclined rear ramp section that is angled upwardly relative to the
horizontal at least approximately 45°. The rear discharge opening
of the exit tunnel occupies approximately an upper quarter of the area of
the rear face of the cutting deck. Grass clippings flow into the upper
portion of a grass collector through this high, steeply angled exit
tunnel to promote even and full filling of the grass collector in the
collecting mode.

Claims:

1. A lawn mower having at least a collecting mode of operation, which
comprises:(a) a cutting deck having a downwardly facing cutting
chamber;(b) a handle assembly extending upwardly and rearwardly from the
cutting deck to allow a user who walks behind the cutting deck to guide
and operate the cutting deck;(c) a rotatable cutting blade within the
cutting chamber for cutting grass, wherein the cutting blade rotates
about a substantially vertical axis of rotation within a substantially
horizontal cutting plane;(d) an exit tunnel located on the deck, wherein
the exit tunnel extends rearwardly from a front inlet opening to a rear
discharge opening located on a rear face of the deck;(e) a grass
collector for receiving and retaining grass clippings therein, the grass
collector having an open mouth substantially overlying the rear face of
the deck and completely overlying the rear discharge opening of the exit
tunnel, wherein the grass collector extends rearwardly from the cutting
deck; and(f) wherein the exit tunnel has a bottom wall that includes a
rear ramp section having a rear edge that forms a lower edge of the rear
discharge opening, wherein the rear ramp section is inclined
approximately at least 45.degree. upwardly relative to the horizontal for
projecting the grass clippings upwardly into an upper portion of the
grass collector.

2. The lawn mower of claim 1, wherein the rear discharge opening has an
open area that covers approximately at least 25% of that portion of the
rear face covered by the open mouth of the grass collector.

3. The lawn mower of claim 1, wherein the rear face has an upper left
quarter, an upper right quarter, a lower left quarter and a lower right
quarter from a perspective of an observer standing behind the rear face
and looking forwardly, wherein the open mouth of the grass collector
substantially covers all four quarters of the rear face, and wherein the
rear discharge opening has an open area that covers approximately one of
the upper quarters of the rear face.

4. The lawn mower of claim 3, wherein the upper quarter covered by the
open area of the rear discharge opening is on that side of the rear face
that the blade rotates towards given a predetermined direction of blade
rotation.

5. The lawn mower of claim 4, wherein the blade rotates in a clockwise
direction from a perspective of an observer standing behind the rear face
and looking forwardly and downwardly, and wherein the wherein the upper
quarter covered by the open area of the rear discharge opening is the
upper right quarter of the rear face.

6. The lawn mower of claim 1, wherein the lawn mower also has a mulching
mode of operation, and further including a pivotal mulch door in the exit
tunnel that pivots between a closed position to block the flow of grass
clippings through the exit tunnel in the mulching mode of operation and
an open position to permit the flow of grass clippings through the exit
tunnel and into the grass collector in the collecting mode of operation.

7. The lawn mower of claim 6, wherein the mulch door pivots about a
substantially horizontal pivot axis at an upper edge of the front inlet
opening to the exit tunnel.

8. A lawn mower having at least a collecting mode of operation, which
comprises:(a) a cutting deck having a downwardly facing cutting
chamber;(b) a handle assembly extending upwardly and rearwardly from the
cutting deck to allow a user who walks behind the cutting deck to guide
and operate the cutting deck;(c) a rotatable cutting blade within the
cutting chamber for cutting grass, wherein the cutting blade rotates
about a substantially vertical axis of rotation within a substantially
horizontal cutting plane;(d) an exit tunnel located on the deck, wherein
the exit tunnel extends rearwardly from a front inlet opening to a rear
discharge opening located on a rear face of the deck, wherein the rear
face has an upper left quarter, an upper right quarter, a lower left
quarter and a lower right quarter from a perspective of an observer
standing behind the rear face and looking forwardly;(e) a grass collector
for receiving and retaining grass clippings therein, the grass collector
having an open mouth that substantially covers all four quarters of the
rear face, wherein the grass collector extends rearwardly from the
cutting deck; and(f) wherein the rear discharge opening has an open area
that covers approximately one of the upper quarters of the rear face.

9. The lawn mower of claim 8, wherein the upper quarter covered by the
open area of the rear discharge opening is on that side of the rear face
that the blade rotates towards given a predetermined direction of blade
rotation.

10. The lawn mower of claim 8, further including a pivotal rear cover
pivotally attached adjacent an upper edge of the rear face, wherein the
rear cover is spring biased to abut against a portion of the rear face
when the grass collector is removed to overlie the rear discharge opening
of the exit tunnel when the grass collector is removed.

11. The lawn mower of claim 10, wherein the lawn mower also has a mulching
mode of operation, and further including a pivotal mulch door in the exit
tunnel that pivots between a closed position to block the flow of grass
clippings through the exit tunnel in the mulching mode of operation and
an open position to permit the flow of grass clippings through the exit
tunnel and into the grass collector in the collecting mode of operation.

12. The lawn mower of claim 11, wherein the rear cover has a portion that
overlies but stands off a portion of the rear discharge opening such that
grass clippings can flow through the exit tunnel if the mulch door is in
the open position thereof and pass out of the exit tunnel against the
rear cover, and wherein the rear cover is shaped to deflect such exiting
grass clippings downwardly onto the ground behind the cutting deck to
alert the operator to the fact that the mulch door is in the open
position.

13. The lawn mower of claim of 10, further including a battery compartment
in an interior of the cutting deck with the battery compartment being
reached by an access opening thereto provided in the rear face, wherein
the access opening to the battery compartment is made accessible when the
rear cover is pivoted upwardly by a user relative to the rear face.

14. The lawn mower of claim 13, wherein the access opening to the battery
compartment is located in the other upper quarter of the rear face.

15. A lawn mower convertible between mulching and collecting modes of
operation, which comprises:(a) a cutting deck which is supported by
rotatable ground engaging members for movement over the ground;(b) a
downwardly facing cutting chamber defined by the deck, the cutting
chamber having a top wall, a peripheral substantially circular sidewall
extending vertically downwardly from the top wall, and an open bottom
circumscribed by the sidewall;(c) a rotatable cutting blade within the
cutting chamber for cutting grass, wherein the cutting blade rotates
about a substantially vertical axis of rotation within a substantially
horizontal cutting plane;(d) an exit tunnel located on the deck, wherein
the exit tunnel extends rearwardly from a front inlet opening to a rear
discharge opening, wherein the front inlet opening is positioned in the
circular sidewall of the cutting chamber at one side of a rear of the
cutting chamber and the rear discharge opening is positioned behind the
front inlet opening and the cutting chamber;(e) a pivotal mulch door
located within the exit tunnel, wherein the mulch door is selectively
pivotal by a user between an open position and a closed position relative
to the exit tunnel about a substantially horizontal axis located adjacent
an upper edge of the front inlet opening of the exit tunnel, wherein the
mulch door in the open position permits grass clippings to pass through
the exit tunnel and into a grass collector associated with the rear
discharge opening of the exit tunnel in the collecting mode of operation,
and wherein the mulch door in the closed position prevents grass
clippings from passing through the exit tunnel such that the grass
clippings must eventually leave the cutting chamber through the open
bottom of the cutting chamber in the mulching mode of operation; and(f)
an operating handle fixedly connected to the mulch door for pivoting the
mulch door between its open and closed positions, wherein the handle
extends from the mulch door through an elongated fore and aft extending
slot leading into an interior portion of the deck with the slot having
front and rear ends, wherein the mulch door is in the open position
thereof when the handle is positioned at one end of the slot and the
mulch door is in the closed position thereof when the handle is
positioned at the other end of the slot.

16. The mower of claim 15, wherein the handle includes an enlarged upper
knob that the user may grasp with the user's hand, and further including
a push button that is biased by a spring to normally extend above the
knob to be engageable by a hand of the user when the user grips the knob,
the push button being depressible by the user to release a detent
engagement that holds the handle in one of the two positions thereof.

17. The mower of claim 16, wherein the push button is part of a slide that
vertically reciprocates relative to the handle, the slide having at least
one locking tab engageable with one of a pair of detents located on one
side of the slot in which the handle pivots.

18. The mower of claim 17 wherein one detent locates and retains the
handle at one end of the slot and the other detent locates and retains
the handle at the other end of the slot.

19. The mower of claim 17, wherein the slide of the push button includes a
pair of locking tabs on opposite sides thereof, and wherein two pairs of
detents are located on opposite sides of the slot to cooperate with the
pair of tabs, one tab cooperating with each pair of detents.

20. The mower of claim 17, wherein the mulch door, a lower portion of the
handle, and a cylindrical hub that pivotally mounts the mulch door rotate
together as a unit, wherein the slide of the push button is carried
within the lower portion of the handle, and wherein the spring that
biases the slide of the push button is located between an underside of
the slide and the top of the cylindrical hub of the mulch door.

Description:

TECHNICAL FIELD

[0001]This invention relates generally to walk behind rotary lawn mowers
that are selectively convertible by the user between collecting and
mulching modes of operation.

BACKGROUND OF THE INVENTION

[0002]Walk behind lawn mowers are well known for mowing grass. Such mowers
comprise a movable cutting deck having a cutting chamber that carries a
substantially horizontal rotary cutting blade. A handle extends upwardly
and rearwardly from deck the deck. An operator grips the handle and walks
behind the mower to guide and control the mower.

[0003]The cutting chamber is formed on the underside of deck 4 and
includes a top wall and a downwardly extending, peripheral side wall. The
cutting chamber has an open bottom facing the ground so that the blade
rotating inside the cutting chamber can contact and sever grass as the
cutting chamber moves over the ground. The cutting chamber is often
shaped as an annular channel extending around most of the periphery of
the cutting chamber adjacent the sidewall of the cutting chamber. The
grass clippings created by the blade will circulate through at least a
portion of this annular channel before leaving the cutting chamber
through an exit tunnel.

[0004]The exit tunnel receives the grass clippings from the cutting
chamber and conducts the grass clippings to a rear discharge opening on
the exit tunnel. The grass clippings are often collected in a grass
collector when such a collector is connected to the discharge opening.
This is the collecting mode of operation of the lawn mower.
Alternatively, the rear discharge opening of the exit tunnel can be
selectively closed by a pivotal mulch door to retain the grass clippings
within the cutting chamber for downward discharge into the cut grass
path. This is the mulching mode of operation of the lawn mower. U.S. Pat.
No. 7,367,174, assigned to the assignee of this invention, discloses a
lawn mower that is selectively convertible by the user between collecting
and mulching modes of operation through the use of a pivotal mulch door
in the exit tunnel.

[0005]While mowers having pivotal mulch doors are known, the mulch doors
are often operated by linkages that are fairly complicated and obtrusive.
Many of these linkages are often contained on the exterior of the mower
and include numerous parts. This leads to extra expense in manufacturing
the mower and decreases the aesthetics of the mower. There is a need in
the art for a mulch door that can be operated by a simple and durable
mechanism that is largely hidden within the mower. The operating
mechanism should be conveniently located and easy to operate by the user.
The operating mechanism desirably should also securely lock or retain the
mulch door in the open or closed positions thereof.

[0006]In addition, the performance of the mower in both its collecting and
mulching modes should be optimized to the maximum extent possible despite
the presence of the mulch door. Often, mowers that are convertible
between collecting and mulching modes might work well in one mode but not
the other, i.e. they might be a good mulching mower but a poor grass
collecting mower or vise versa. Accordingly, there is also a need for a
mower of this type which has excellent performance in both modes of
operation.

SUMMARY OF THE INVENTION

[0007]One aspect of this invention relates to a lawn mower having at least
a collecting mode of operation. The mower comprises a cutting deck having
a downwardly facing cutting chamber. A handle assembly extends upwardly
and rearwardly from the cutting deck to allow a user who walks behind the
cutting deck to guide and operate the cutting deck. A rotatable cutting
blade within the cutting chamber cuts grass by rotating about a
substantially vertical axis of rotation within a substantially horizontal
cutting plane. An exit tunnel located on the deck extends rearwardly from
a front inlet opening to a rear discharge opening located on a rear face
of the deck. A grass collector for receiving and retaining grass
clippings has an open mouth substantially overlying the rear face of the
deck and completely overlying the rear discharge opening of the exit
tunnel. The grass collector extends rearwardly from the cutting deck. The
exit tunnel has a bottom wall that includes a rear ramp section having a
rear edge that forms a lower edge of the rear discharge opening. The rear
ramp section is inclined approximately at least 45° upwardly
relative to the horizontal for projecting the grass clippings upwardly
into an upper portion of the grass collector.

[0008]One aspect of this invention relates to a lawn mower having at least
a collecting mode of operation. The mower comprises a cutting deck having
a downwardly facing cutting chamber. A handle assembly extends upwardly
and rearwardly from the cutting deck to allow a user who walks behind the
cutting deck to guide and operate the cutting deck. A rotatable cutting
blade within the cutting chamber cuts grass by rotating about a
substantially vertical axis of rotation within a substantially horizontal
cutting plane. An exit tunnel located on the deck extends rearwardly from
a front inlet opening to a rear discharge opening located on a rear face
of the deck, wherein the rear face has an upper left quarter, an upper
right quarter, a lower left quarter and a lower right quarter from a
perspective of an observer standing behind the rear face and looking
forwardly. A grass collector receives and retains grass clippings
therein. The grass collector has an open mouth that substantially covers
all four quarters of the rear face and extends rearwardly from the
cutting deck. The rear discharge opening of the exit tunnel has an open
area that covers approximately one of the upper quarters of the rear
face.

[0009]Yet another aspect of this invention relates to a lawn mower
convertible between mulching and collecting modes of operation. The mower
comprises a cutting deck which is supported by rotatable ground engaging
members for movement over the ground. A downwardly facing cutting chamber
defined by the deck has a top wall, a peripheral substantially circular
sidewall extending vertically downwardly from the top wall, and an open
bottom circumscribed by the sidewall. A rotatable cutting blade within
the cutting chamber for cuts grass by rotating about a substantially
vertical axis of rotation within a substantially horizontal cutting
plane. An exit tunnel located on the deck extends rearwardly from a front
inlet opening to a rear discharge opening. The front inlet opening is
positioned in the circular sidewall of the cutting chamber at one side of
a rear of the cutting chamber and the rear discharge opening is
positioned behind the front inlet opening and the cutting chamber. A
pivotal mulch door within the exit tunnel is selectively pivotal by a
user between an open position and a closed position relative to the exit
tunnel about a substantially horizontal axis located adjacent an upper
edge of the front inlet opening of the exit tunnel. The mulch door in the
open position permits grass clippings to pass through the exit tunnel and
into a grass collector associated with the rear discharge opening of the
exit tunnel in the collecting mode of operation. The mulch door in the
closed position prevents grass clippings from passing through the exit
tunnel such that the grass clippings must eventually leave the cutting
chamber through the open bottom of the cutting chamber in the mulching
mode of operation. An operating handle is fixedly connected to the mulch
door for pivoting the mulch door between its open and closed positions.
The handle extends from the mulch door through an elongated fore and aft
extending slot leading into an interior portion of the deck with the slot
having front and rear ends. The mulch door is in the open position
thereof when the handle is positioned at one end of the slot and the
mulch door is in the closed position thereof when the handle is
positioned at the other end of the slot.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010]This invention will be described more completely in the following
Detailed Description, when taken in conjunction with the following
drawings, in which like reference numerals refer to like elements
throughout.

[0011]FIG. 1 is a perspective view of a lawn mower according to this
invention, particularly illustrating the mower without a grass collector;

[0012]FIG. 2 is a perspective view of the mower of FIG. 1, particularly
illustrating the mower with a grass collector separated from the rear of
the mower;

[0013]FIG. 3 is a perspective view similar to FIG. 2, particularly
illustrating the mower with a grass collector attached to the rear of the
mower;

[0014]FIG. 4 is a perspective view of the mower of FIG. 1, particularly
showing a rear cover in a lowered position covering the rear discharge
opening of the exit tunnel;

[0015]FIG. 5 is a perspective view similar to FIG. 4, but showing the rear
cover having been separated from the rear of the mower;

[0016]FIG. 6 is an enlarged perspective view of the rear of the mower as
shown in FIG. 5, particularly illustrating a removable battery having
been removed from a battery compartment through the rear face of the
mower and illustrating the pivotal mulch door in its installed position
within the mower with the mulch door being closed in the exit tunnel to
place the mower into the mulching mode of operation;

[0017]FIG. 7 is a perspective view similar to FIG. 6, but showing the
pivotal mulch door also having been removed from the mower and positioned
behind the mower;

[0018]FIG. 8 is a perspective view of a portion of the mower of FIG. 1
with a portion of the sidewall of the cutting chamber having been
removed, particularly illustrating the handle of the mulch door in a rear
position corresponding to the closed position of the mulch door in the
mulching mode of operation;

[0019]FIG. 9 is a perspective view similar to FIG. 8, but showing the
handle in a front position corresponding to an open position of the mulch
door in the collecting mode of operation;

[0020]FIG. 10 is a partial cross-sectional view of the handle of the mulch
door as shown in FIG. 9, particularly illustrating the push button of the
handle and its engagement with a front detent for holding the handle in
the front position;

[0021]FIG. 11 is a partial cross-sectional view similar to FIG. 10, but
with the handle having been removed to show the curved rail forming the
front and rear detents for holding the handle in the front and rear
positions thereof, respectively;

[0022]FIG. 12 is a partial cross-sectional view similar to FIG. 10,
particularly illustrating only the push button of the handle and its
engagement with the rear detent for holding the handle in its rear
position;

[0023]FIG. 13 is a partial, longitudinal cross-sectional view of the rear
of the mower of FIG. 1 taken through the exit tunnel, particularly
illustrating the mulch door in a closed position in the exit tunnel to
place the mower into its mulching mode of operation;

[0024]FIG. 14 is a cross-sectional view similar to FIG. 13, but now
showing a grass collector having been attached to the rear of the mower
and with the mulch door in an open position in the exit tunnel to place
the mower into its collecting mode of operation;

[0025]FIG. 15 is a transverse cross-sectional view of the mower as shown
in FIG. 1 taken through the rear of the cutting chamber just forward of
the front inlet opening of the exit tunnel, particularly illustrating the
exit tunnel from the front thereof;

[0026]FIG. 16 is a cross-sectional view similar to FIG. 15, but with the
shroud that covers the mulch door and battery having been removed to
illustrate both the mulch door and the battery from the front thereof;

[0027]FIG. 17 is a top plan view of the bottom of the exit tunnel and the
curved rear scroll that forms the rear portion of the sidewall of the
cutting chamber; and

[0028]FIG. 18 is a longitudinal cross-sectional view through the exit
tunnel and sidewall portion depicted in FIG. 17, particularly
illustrating the steeply inclined rear ramp of the exit tunnel.

DETAILED DESCRIPTION

[0029]A walk behind lawn mower according to this invention is generally
illustrated as 2 in FIG. 1. Mower 2 includes a cutting deck 4 supported
for rolling over the ground by four wheels 6 at the corners of deck 4.
Short ground engaging rollers could be substituted for each wheel 6 or
long rollers spanning the width of deck 4 could be substituted for each
pair of wheels 6 or both pairs of wheels 6 if so desired. The center of
deck 4 has a slight depression or indentation in which an internal
combustion engine 8 is mounted. Other power sources, such as an electric
motor, fuel cell, hybrid gas-electric power system, etc., could be used
in place of engine 8. Engine 8 has a vertical drive spindle (not shown)
that extends down through the top wall of deck 4.

[0030]An upwardly and rearwardly extending handle assembly 9 allows an
operator to walk behind mower 2 to guide and operate mower 2. In a
self-propelled version of mower, handle assembly 9 can include a slidable
handle grip 11 for controlling the ground speed of mower 2. Slidable
handle grip 11 is disclosed in more detail in U.S. Pat. No. 6,982,083,
which is hereby incorporated by reference.

[0031]A rotary cutting blade 10 is mounted on the vertical spindle of
engine 8 beneath the top wall of deck 4 to rotate in a substantially
horizontal cutting plane. Deck 4 includes an annular cutting chamber
extending around deck 4 with the cutting chamber being bounded by an
outer, circumferential peripheral sidewall 12 extending downwardly from a
top wall 13 of the cutting chamber. As cutting blade 10 is rotated in its
horizontal cutting place, sharpened cutting edges at the tips of cutting
blade 10 sever the grass and create grass clippings. The tips of cutting
blade 10 have trailing upturned sails that create a circumferential
airflow. Thus, the grass clippings are circulated within the annular
cutting chamber in the direction of the arrows A in FIG. 1 which
corresponds to the direction in which the blade is rotated.

[0032]How the grass clippings exit from the cutting chamber depends upon
whether mower 2 is in a collecting or a mulching mode of operation. In
the collecting mode as shown in FIG. 3, a grass collector 14 having an
open mouth 15 is attached to the rear of mower 2. The open mouth 15 of
grass collector 14 can be seen in FIG. 2. In addition as shown in FIG.
13, an exit tunnel 16 on top of deck 4 at the right rear end of mower 2
is open to provide a passageway through the rear of mower 2. Thus, the
grass clippings after being cut flow in the direction of the arrows A and
then exit directly through exit tunnel 16 during their first pass through
the cutting chamber to be deposited within and collected by grass
collector 14.

[0033]In the mulching mode, grass collector 14 may be present as shown in
FIG. 3 or may be removed as shown in FIG. 1. Regardless of whether or not
grass collector 14 is present, exit tunnel 16 is selectively closed by
the user of mower 2. Now, the grass clippings cannot leave the cutting
chamber through exit tunnel 16 but are circulated around the cutting
chamber in the direction of the arrows A. This recirculation might last
for a number of passes around the cutting chamber until the grass
clippings are cut and recut and eventually fall downwardly into the cut
grass path through the open bottom face of the cutting chamber. In the
mulching mode, these grass clippings, which have been driven downwardly
into and largely hidden by the remaining standing grass in the cut grass
path, will decompose and serve as nutrients to the turf.

[0034]Referring now to FIGS. 4-7, the rear of mower 2 has a generally
planar rear face 18 that is inclined slightly forwardly as it rises. A
pivotal rear cover 20 has a pair of trunnions 22 extending to either side
thereof as best shown in FIG. 5. Trunnions 22 pivotally mount cover 20 in
short, circular hubs 21 or openings on support flanges 23 along the upper
edge of rear face 18 of mower 2. See FIG. 9. This avoids the expense of
an elongated, transverse pivot rod for journaling cover 20 since
trunnions 22 can be molded as part of cover 20. Preferably, cover 20 is a
one piece molded plastic part having a raised center channel 24 and a
side flap 26 on either side of channel 24. The lower edge 28 of channel
24 forms a hand grip for allowing a user to manually raise cover 20

[0035]Cover 20 rotates about a substantially horizontal pivot axis x1 from
a lowered position in which side flaps 26 of cover 20 abut against rear
face 18 of mower 2, as shown in FIG. 4, to a raised position in which
cover 20 overlies and rests atop the front of grass collector 14, as
shown in FIG. 3. Two torsion springs 30, best shown in FIG. 6, act
between cover 20 and some other portion of mower 2 to bias cover 20 in
the direction of the arrow B in FIGS. 4 and 5. Thus, cover 20 is normally
disposed in its lowered position with side flaps 26 abutting against rear
face 18 of mower 2 along their lower edges 27. Cover 20 stands off or is
spaced away from rear face 18 of mower 2 as illustrated by the gap g in
FIG. 13. The user can insert his or her hand into the gap g and grip
lower edge 28 of channel 24 to manually raise cover 20 against the bias
of torsion springs 30. This is done when attaching grass collector 14 to
mower 2 or to otherwise gain access to rear face 18 of mower 2.

[0036]One reason for gaining access to rear face 18 of mower 2 is to
remove or install a battery 32 that is carried on mower 2. Battery 32
could have different purposes on mower 2. In a simple system, battery 32
is simply a source of electrical power used for starting engine 8 when
engine 8 is equipped with an electric starter. In a more complex system,
battery 32 could also comprise a source of electrical power for powering
an electric motor(s) used either for rotating cutting blade 10 or for
wheel drive propulsion or both. In this latter use, battery 32 could be
part of a battery only drive system or be part of an engine/battery
hybrid drive system.

[0037]Regardless of the use of battery 32 on a particular mower, a battery
compartment 34 is provided that is substantially enclosed within the body
of mower 2. As best shown in FIG. 6, battery compartment 34 is accessed
through an access opening 36 provided in rear face 18 of mower 2. Battery
compartment 34 includes a substantially horizontal floor 38 which
receives a slidable tray or cradle 40. Battery 32 is dropped down into
cradle 40 and is retained in cradle 40 by a short, upwardly projecting
lip 42 extending around the front and sides of cradle 40.

[0038]The rear of cradle 40 includes an upwardly extending rear wall 44
that extends above battery 32 such that the upper edge 46 of the rear
wall is exposed. This edge 46 forms a grip for allowing the user to slide
cradle 40 into or out of battery compartment 34. When cradle 40 has been
inserted into the compartment, cradle 40 is secured in place by a bolt 48
that passes through a rear flange 50 of cradle 40 and is tightened down
into a threaded boss 52 formed on a ledge of rear face 18 immediately
below the access opening to battery compartment 34. Suitable electrical
connectors 54 are provided in battery compartment 34 for connecting
battery 32 to whatever system on mower 2 uses the electrical power stored
in battery 32.

[0039]This structure provides an easy method for servicing or replacing
battery 32 if need be. The user can raise battery 32 cover, unscrew bolt
48, grab the grip provided by upper edge 46 of the rear wall of cradle
40, and then simply slide cradle 40 and battery 32 out of mower 2 through
rear face 18 of mower 2. The electrical connectors 54 can be disconnected
either prior to or after cradle 40 is slid out. This slide in and slide
out cradle 40 eases the task of battery maintenance and is user friendly.
In addition, battery 32 is conveniently hidden within the body of mower 2
during use, but is easily removable from mower 2 without having to
disassemble any parts of mower 2. All the user has to do is pivot cover
20 upwardly, unscrew cradle 40, and pull battery 32 out by sliding cradle
40 out. No substantial numbers of additional parts are required since
cover 20 is needed in any event for abutting against rear face 18 of
mower 2 to close off exit tunnel 16 when grass collector 14 is not
attached to mower 2.

[0040]Referring further to FIG. 6, the rear discharge opening 56 of exit
tunnel 16 is depicted to the right of access opening 36 to battery
compartment 34. Rear discharge opening 56 is located in rear face 18 of
mower 2. In FIG. 6, the viewer is looking into exit tunnel 16 through
rear discharge opening 56 towards the front inlet opening 58 of exit
tunnel 16. However, front inlet opening 58 of exit tunnel 16 is blocked
in FIG. 6 by a pivotal mulch door 60, which is shown in the closed
position thereof.

[0041]As is also seen in FIG. 6, rear discharge opening 56 of exit tunnel
16 has a height h and a width w that define an open area. This open area
is approximately 25 to 35% of the area of rear face 18 of mower 2.
Moreover, rear discharge opening 56 of exit tunnel 16 occupies one of the
upper quarters of rear face 18 of mower 2. The lower edge 57 of rear
discharge opening 56 is also approximately half way up the height of rear
face 18 of mower 2. The significance of this positioning will be
described in more detail hereafter.

[0042]In FIG. 7, mulch door 60 has been removed from the interior of mower
2 and pulled out. Now, the viewer can look all the way through exit
tunnel 16 and down into the interior of the cutting chamber. Mulch door
60 and a lower portion of an operating handle 62 for mulch door 60 are
molded together out of plastic as a single piece. Mulch door 60 has a
cylindrical hub 64 formed therewith. The ends of cylindrical hub 64
pivotally journal mulch door 60 in circular openings 66 in walls in a
shroud 68 that is part of the body of mower 2. As shown in FIG. 7, the
rear of mulch door 60 has a plurality of strengthening ribs 69. The front
of mulch door 60, hidden in FIG. 7 but visible in FIG. 8, is smooth.

[0043]Referring now to FIGS. 8-12, the aforementioned shroud 68 in which
mulch door 60 is pivoted is seen in FIG. 8 from the front. Shroud 68 has
an elongated fore and aft slot 70 through which handle 62 extends when
mulch door 60 is in place in exit tunnel 16. The lower portion of handle
62 has an enlarged knob 72 secured to the top thereof. FIG. 8 depicts
handle 62 in a raised rear position thereof corresponding to the closed
position of mulch door 60. Note that mulch door 60 can be seen in FIG. 8
having been swung down into engagement with the bottom of exit tunnel 16
to close or block off front inlet opening 58 to exit tunnel 16
substantially immediately behind front inlet opening 58. In achieving
this pivoting motion, mulch door 60 pivots about the substantially
horizontal pivot axis defined by the axis of hub 64. This pivot axis is
labeled x2 in FIG. 8.

[0044]Referring now to FIG. 9, to open exit tunnel 16, namely to pivot
mulch door 60 upwardly towards the top of exit tunnel 16, the user must
grab knob 72 of handle 62 and must push handle 62 downwardly from the
upper rear end of slot 70 into engagement with the lower front end of
slot 70. When this occurs, mulch door 60 is swung up inside exit tunnel
16 until it folds up generally adjacent the top wall of exit tunnel 16.
Note mulch door 60 is no longer visible in FIG. 9 since it has moved up
out of view in this lowered position of handle 62. In this position of
handle 62, mower 2 is in the collecting mode and the grass clippings can
exit the cutting chamber and move into grass collector 14 by passing
through the now open exit tunnel 16.

[0045]Preferably, a retainer is provided for locking or holding mulch door
60 in its open or closed positions. One embodiment of such a retainer is
illustrated herein. That embodiment includes a depressible push button 74
carried on top of handle 62 within the enlarged knob. As shown in FIG. 9,
the push button has a dog bone or barbell shape received inside a
similarly shaped cavity in knob 72. The user can push down on push button
74 in the direction of the arrow C in FIG. 10 with the user's thumb or
palm as the user grips knob 72 with his or her hand.

[0046]Referring further to FIG. 10, push button 74 has an extended slide
76 that passes down through the lower portion of handle 62. Each side of
slide 76 includes a locking tab 78 formed thereon with only one such
locking tab 78 being visible in FIG. 10 as locking tab 78 on the other
side of slide 76 is hidden. Each side of slot 70 has a curved rail 80 on
an underside of shroud 68 adjacent slot 70 with the ends of curved rail
80 forming both an upper rear detent 82r and a lower front detent 82f.
See FIG. 11 for an illustration of front and rear detents 82.

[0047]A compression spring 84 is provided beneath slide 76 of push button
74. Spring 84 extends between the bottom of slide 76 and the top of hub
64 of mulch door 60. Spring 84 can be partially seen in FIG. 10. Spring
84 biases push button 74 upwardly relative to handle 62 in the direction
of the arrow D in FIG. 10. Thus, the top of push button 74 has a normal
position in which it is extended a small distance above the surface of
knob 72 of handle 62, as best shown in FIGS. 9 and 10.

[0048]In FIG. 10, handle 62 is shown locked in its lower front position.
Locking tabs 78 on slide 76 of push button 74 are located in the lower
front detents 82f on either side of slot 70. To release handle 62 for
movement, the user simply grips handle 62 and pushes down on push button
74 with his or her thumb or palm to depress locking tabs 78 against the
bias of spring 84 until locking tabs 78 have cleared the front detents
82f. The operator then simply pivots handle 62 up the length of slot 70
until handle 62 engages against the upper rear end of slot 70. At this
point, the operator can release handle 62 and push button 74 simply by
removing his or her hand from handle 62. The bias of spring 84 will then
cause slide 76 to rise to engage locking tabs 78 with the upper rear
detents 82r with spring 84 biasing also causing push button 74 to pop
back out of the top of knob 72. See FIG. 12. Thus, mulch door 60 can be
moved between its open and closed positions, and can be retained in
either of its open and closed positions, by a simple, intuitively
operable operating handle 62 that is merely slid from one end of a fore
and aft slot 70 to another to select either of the two desired positions
and that has a simple release provided by push button 74.

[0049]Referring now to FIGS. 15-18, the rear portion of the cutting
chamber is formed by an arcuate scroll 86 having a vertical face 88.
Scroll 86 is individually depicted in FIG. 17. Scroll 86 is secured
within a metal casting that forms much of the rest of deck 4. When in
place, the vertical face 88 of scroll 86 forms a continuation of that
portion of the circumferential, peripheral sidewall 12 of the annular
cutting chamber provided in the metal casting. Thus, as shown in FIG. 15,
the tip of cutting blade 10 sweeps past this sidewall 12, i.e. sweeps
past the vertical face 88 of scroll 86, as it rotates around within the
cutting chamber. A bottom half of exit tunnel 16 is formed as part of
scroll 86 as shown in FIGS. 17 and 18. The top half of exit tunnel 16 is
formed as part of shroud 68.

[0050]The bottom half of exit tunnel 16 formed in scroll 86 has an
upwardly facing U-shaped defined by a bottom wall 90 of exit tunnel 16
and by lower sections 92 of spaced side walls of exit tunnel 16. Bottom
wall 90 of exit tunnel 16 includes three separate sections, namely an
entrance section 94 at the beginning of exit tunnel 16 immediately in
back of front inlet opening 58, a curved or arcuate middle transition
section 96, and a rather steeply inclined rear ramp section 98. See FIG.
18. Rear ramp section 98 is steeply angled upwardly relative to
horizontal, as indicated by the angle α FIG. 18, in the range of
45° to 60° and preferably approximately 52° to
57°, with the end of rear ramp section 98 comprising the lower
edge 57 of rear discharge opening 56 of exit tunnel 16. In addition, the
total rise on bottom wall 90 of exit tunnel 16 from the lower edge 59 of
front inlet opening 58 to the lower edge 57 of rear discharge opening 56
is approximately equal to the length of exit tunnel 16. This
configuration effectively locates rear discharge opening 56 of exit
tunnel 16 quite high on rear face 18 of mower 2 as seen in FIG. 6.

[0051]The high location of rear discharge opening 56 of exit tunnel 16 in
conjunction with the steeply inclined rear ramp section 98 of bottom wall
90 of exit tunnel 16 directs the grass clippings from exit tunnel 16 into
the front of grass collector 14 in a direction against the front of the
top wall of grass collector 14. This is shown by the arrows E in FIG. 14.
This optimizes the performance of mower 2 in its collecting mode. Grass
clippings are deposited into grass collector 14 in a manner that most
efficiently loads the grass clippings into grass collector 14 without
such clippings dribbling back out of exit tunnel 16.

[0052]The entire exit tunnel 16 is shown in longitudinal cross-section in
FIGS. 13-15. This includes the bottom half of exit tunnel 16 formed by
scroll 86 shown in FIGS. 18 and 19. The remainder of exit tunnel 16,
namely the top half of exit tunnel 16 comprising the upper sections 100
of the side walls and the top wall 102 of exit tunnel 16, is formed in
shroud 68 that forms part of the body of mower 2. Together, these two
pieces, namely scroll 86 and shroud 68, form the complete exit tunnel 16.
In addition, shroud 68 serves to pivotally journal mulch door 60 in
openings 66 and includes slot 70 in which handle 62 of mulch door 60
moves. Shroud 68 is simply bolted to the top wall of the metal deck
casting by a plurality of bolts 104 shown in FIG. 16.

[0053]Referring now specifically to FIG. 13, mulch door 60 is shown in its
closed position. In this position, mulch door 60 inclines downwardly and
slightly rearwardly from its pivot axis at the front of exit tunnel 16
where top wall 102 of exit tunnel 16 begins to rise in height relative to
the top of deck 4. The free rear end of mulch door 60 engages bottom wall
90 of exit tunnel 16 generally along the line or junction between
entrance section 94 and middle transition section 96. As shown in FIG.
13, this blocks exit tunnel 16 to the passage of grass clippings through
exit tunnel 16 and places mower 2 into its mulching mode of operation.

[0054]If mulch door 60 is pivoted into its open position without grass
collector 14 being attached to the rear of mower 2, cover 20 will remain
closed due to the bias of torsion springs 30. Thus, the user and
bystanders are still protected against the passage of thrown objects or
the like due to the presence of cover 20 even though the user might
inadvertently leave mulch door 60 in the open position. However, cover 20
stands off from rear face 18 of mower 2 as shown by the gap g in FIG. 13.

[0055]Thus, if the user operates mower 2 with grass collector 14 removed
and mulch door 60 inadvertently left open, the grass clippings can pass
through the gap g. These grass clippings will be directed downwardly
towards the ground by cover 20 and will be deposited on the ground in
back of mower 2. This serves to alert the user that mulch door 60 is
still open. The user can then pivot mulch door 60 to its closed position
to seal off exit tunnel 16 to the passage of any grass clippings.

[0056]FIG. 14 shows the orientation of mulch door 60 when mulch door 60 is
open and grass collector 14 is attached, i.e. mower 2 is in the
collecting mode. In this position, mulch door 60 has been folded up
against top wall 102 of exit tunnel 16. Mulch door 60 is only slightly
less inclined than the steeply inclined rear ramp section 98 of bottom
wall 90 of exit tunnel 16, i.e. mulch door 60 in its open position is
approximately parallel to rear ramp section 98. As shown in FIG. 14 by
the arrows E, the stream of grass clippings will be thrown in a direction
that causes the stream to impact against the top wall of grass collector
14 in the front half of grass collector 14. Again, as noted earlier, the
Applicants have found that this orientation and the size and placement of
rear discharge opening 56 relative to the open mouth of grass collector
14, namely rear discharge opening 56 is about 25 to 35% of the area of
the open mouth of grass collector 14 and is positioned in an upper
quarter of grass collector 14, to be effective in causing even and full
filling of grass collector 14. Thus, performance as a grass collecting
lawn mower has been optimized.

[0057]Yet, in the mulching mode, performance is also very good. Mulch door
60 hangs down and pivots from a front end of exit tunnel 16 to seal off
exit tunnel 16 substantially at or slightly behind front inlet opening 58
to exit tunnel 16. Essentially, when mulch door 60 is in place, there is
little disruption in the normal annular shape of the cutting chamber.
This aids in mulching since exit tunnel 16 will not fill or pack with
grass clippings since exit tunnel 16 is closed off at front inlet opening
58 rather than rear discharge opening 56.

[0058]Various modifications of this invention will be apparent to those
skilled in the art. For example, the slide in-slide out mounting of
battery 32 in an access opening 34 in rear face 18 of mower 2, which
opening 34 is normally closed off by cover 20, could be used in mowers
other than those incorporating exit tunnel 16 and mulch door 60.

[0059]In addition, mower 2 could be provided with other than the above
described collecting and mulching modes of operation. For example,
sidewall 12 of the cutting chamber could be provided with a selectively
openable side discharge opening (not shown) for discharging grass
clippings to one side of mower 2. In addition, instead of using grass
collector 14, a rear discharge chute could be mated with rear discharge
opening 56 for discharging grass clippings to the rear of mower 2. Thus,
the scope of the invention shall be limited only by the appended claims.